Apparatus for regulating voltage.



No. 773,398. PATENTED OCT; 25, 1904.

M. LEBLANG.

APPARATUS FOR REGULATING VOLTAGE.

APPLICATION FILED JAN. 5, 1903. I

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PATENTED OCT. 25, 1904.

M. LEBLANC.

APPARATUS FOR REGULATING VOLTAGEL APPLICATION FILED JAN. 5, 1903.

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PATENTED OCT. 25, 1904.

, M. LEBLANG.

APPARATUS FOR REGULATING VOLTAGE.

APPLIOATIONIILED JAN. 5, 1903.

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WITNESSES. 5M2? W (7 4/ MAURICE LEBLANO,

Patented October 25, 1904.

PATENT OFFICE.

OF PARIS, FRANCE.

APPARATUS FOR REGULATING VOLTAGE.

SPECIFICATION forming part of Letters Patent No. 773,398, dated October 25, 1904:.

Application filed January 6, 1903. Serial No. 137,933. (No model.)

To (all whmn it may concern:

Be it known that I, MAURICE LEBLANO, a citizen of the Republic of France, residing at Paris, France, have invented a new and useful Apparatus for Regulating Voltage, of which the following is a specification.

My invention is designed to automatically regulate the voltages of electrical apparatus, more particularly the voltage of alternators or induction-machines when used as generators. In this case the strength of the exciting-current of the generators is varied from moment to moment in such a manner as to secure a constant voltage or a voltage of predetermined or desired value whatever be the causes which tend to vary this voltage and whether this tendency to variation of voltage is due to a variation of output or to a variation of speed of the alternators. This automatic regulation I obtain by purely electrical means and by a system of excitation which permits the use of alternators or of induction-machines having a great reactance; but despite the reactance the variations of the excitingcurrent may be large and are obtained almost instantaneously. In fact, my system of voltage regulation may be applied to alternators which are supplied with the customary deadening-circuits for forcibly deadening the oscillatory movements known as hunting. To this end I employ a source of voltage varying with the voltage of the line and a source of voltage opposed thereto, which may have a uniformly-constant value or, more broadly stated, some predetermined or desired value. These opposing voltages give rise to a regulating-current which may change its direction under a variation of the main-line voltage, and this current is used either directly or through the intervention of a relay to controlthe strength of the field of the exciter to maintain the voltage supplied by the alternator at the desired value.

- In order to fix ideas, I will show my invention as applied to a generator of alternating currents, and more particularly to a threephase alternator. It will be understood, however, that my invention is equally applicable to other types of electrical generators and motors.

In the drawings, Figure 1 shows my system in diagram. Fig. 2 shows the field-magnet of one of my regulating-machines. Figs. 3, A, and 5 show the field-windings of this regulating-machine, and Fig. 6 shows a modification.

I have shown two three-phase alternators having their field-windings T1 and T2 coupled in parallel and having their armatures T and T supplying electrical energy in the shape of triphase currents to the main lines I, II, and III. Connected to this main line through the switches U U U is the commutatingmachine or rotary converter 1, caused in any desired way to run at a constant speed and impressing upon the circuit J, connected to its brushes C D, a voltage which is strictly proportional to the voltage of the main line. This commutating-machine has an armature A and a shunt field-winding B. There is also a series field-winding B displaced ninety degrees, magnetically considered, from the shunt field-winding, as indicated in Fig. 1. This series field-winding B is designed to overcome the eifect of armature reaction, as will more fully appear. It is to be understood, then, that this rotary converter has been shown as a source of electromotive force proportional to the electromotive force of the line, such as I may employ. Opposed to this source of electromotive force, which is proportional to the electromotive force of the line, is any source of electromotive force of constant value. In the present case I have shown for such source of constant electromotive force a direct-current dynamo 2, having an armature E, a shunt field-winding F, brushes Gr H, and a series field winding F displaced ninety degrees from the shunt-winding F, so as to overcome the effect of armature reaction.

The magnitude of the voltage furnished by the source of constant voltage 2 is preferably so chosen that when the voltage of the line is normal the voltage furnished by the source 2 will be equal and opposite to the voltage furnished by the source 1, so that under these conditions no current flows in the circuit J. When the line voltage falls below normal, the voltage furnished by the source 2 will be greater than the voltage furnished by the source 1, so that a current will traverse the circuit J in a given direction. \Vhen the line voltage increases above normal, the voltage furnished by the source 2 will be less than the voltage furnished by the source 1, so that a current will now traverse the circuit J in the opposite direction. The regulatingcurrent in the circuit J thus produced is utilized to vary the excitation of the alternator to bring the voltage supplied by it to the line back to normal. There are manifestly numerous ways in which this regulating-current in the circuit J can be utilized through the eXciter to keep the alternator voltage normal, all of which would fall within the scope of my invention broadly considered; but since it is desirable that a small variation of the regulating-current shall produce a considerable variation in the field excitation of the alternator I prefer to employ a relaydynamo 4, which has a field-winding Kin the regulating-circuit J, so that when the regulating-current is Zero the field strength of this dynamo 4 and the current supplied by its brushes are both zero. hen the regulatingcurrent is in a given direction, the current supplied by the brushes of the dynamo t will also be in a given direction, and vice versa. The current supplied by the brushes of the dynamo 4 will thus change in direction in accordance with the changes in direction of the regulating-curreut in the circuit J; but the magnitude of the relay-dynamo current will be proportionately much greater than that of the regulating-current.

The dynamo i is driven at a constant velocity in any suitable manner as, for instance, by pulley Iand in order to overcome the effect of armature reaction I preferably again employ a series field-winding K, which is displaced ninety degrees from the field-winding K.

The eXciter 3 has a field-winding M in circuit with the armature of the dynamo 4. It has a shunt field-winding O, which cooperates with the field-winding M. Finally, it has a series field-winding N displaced ninety degrees from the field-windings M O for the purpose of overcoming armature reaction. The armature P, the commutator, the brushes Q R, and the pulley I, which drives the armature I (and may also drive the armature 1d,) are all of the usual type. It need merely be added that the brushes Q It of the exciter 3 are in circuit with the field-windings T1 T2 of the alternators whose voltages are to be regulated.

The operation of the system as thus far described will now be clear. When the voltage in the line is normal, the regulating-current in the circuit J is Zero, which means that my regulating devices are, in effect, out of action. This is as it should be; but when the voltage in the line falls, and with it the voltage supplied by the source I, a regulating-current will flow in a given direction. This will cause a current to flow in a given direction in the winding M of the eXciter 3, and the direction of this winding is so chosen that the current in the direction just specified will add to the magnetizing effect produced by the shuntwinding 0. The excitation of the exciter being thus increased its armature-circuits furnish a stronger current to the field-windings T1 T2 of the alternators, which alternator-s thereupon furnish an increased voltage to the line, so as to restore the line voltage to normal. Should the line voltage at any time rise above normal, a regulating-current will flow in the circuitJ in a direction contrary to that just referred to. This will have for its result that a current will flow in the winding M of the eXciter 3 in a direction to subtract from the effect of the shunt-winding O. The excitation of the exciter having thus been decreased, the amount of current which its armatu re supplies to the alternator-field will be correspondingly decreased, so that the voltage which the alternator supplies to the line will be decreased until this last-mentioned voltage has regained its normal value.

I need hardly remark that since the only efi ect of the relay-dynamo 4 is to cause a greater current to flow in the winding M of the exciter 3 than flows in the winding K it will be possible to omit this relay-dynamo and to use the winding K directly on the exciter 3.

In the above description I have assumed that it is desired to maintain the line voltage at a constant fixed Value; but in certain cases it is of advantage that the line voltage should increase in a PI'OClCtOIIIlIDQCl manner with the output. Under this aspect of my invention the invariably constant line voltage, the production of which I have specifically described in the preceding paragra 'ihs, is a specific case of a line voltage of predetermined value when that predetermined value becomes constant.

It will be clear from what precedes that the source of constant voltage 2 determines the voltage of the line. If the voltage furnished by this source 2 is constant, the line voltage is constant. If the voltage of the source 2 has some predetermined value, the line voltage will have a corresponding predetermined value. To have the line voltage vary with the output, it is then merely necessary to have the voltage of the source 2 vary with the output. To accomplish this result, I add to the field-winding F of the dynamo 2 a second field-winding F tapped from the circuit S (see Fig. 6) in such a manner that these two field-windings conspire in their effects. \Vhen the output of the alternators increases, the intensity of the exciting-currents in the alternators has increased proportionately, so that the strength of the current flowing in the winding F is caused to increase in proportion to the output; but this means that the voltage furnished by the dynamo 2 will increase with the output, or that the line voltage will increase with the output.

When I use the dynamo 2 as a source of constant electromotive force for the regulating-circuit J, it is manifestly desirable to strongly saturate its field; but when it is desired to have the dynamo 2 furnish to the regulating-circuit a voltage which varies with l the output of the alternators the magnetic circuits of the machine 2 should not be completely saturated by the action of the shuntcoil F, so as to leave room for the additional effect of the field-coil F ln constructing the machines 3 and 4E several considerations are to be borne in mind. For instance, the magnetic fluxes therein should vary rapidly and be always practically proportional to the intensity of the currents which produce them. This requires that the iron of their structure should be well laminated. Again, it is desirable that the potential energy stored in the machines 3 and at should be as small as possible. This requires the magnetic leakage to be reduced to a minimum, so that we are led to use a stator like those of induction-machines. It is furthermore desirable that the requisite number of ampereturns for producing a given iiux should be as small as possible. This means that we must employ small air-gaps and that we must work below magnetic saturation at all points.

' In addition to all this it is desirable to avoid the effect of armature reactions, and this is the purpose of the series windings N and K, as has been pointed out above. Taking the field-coil N, for instance, I wind it, in fact, in such a manner that it develops upon the stator along the surface of the air-gap as many ampere-turns as are developed by the rotor, but having their magnetizing force acting in a contrary direction. The same remark applies to the field-coil K.

if the stator structures which I prefer to employ were of the type ordinarily used in continuous-current dynamos, it would manifestly be sufficient to wind the coils K on auxiliary poles in line with the armaturebrushes, the coils K being wound on poles at right angles to the line of the armaturebrushes; but as the stator structures which I prefer to employ in the machines 3 and4 are of the type usedin induction-machines a little further description of the method of applying the field-coils to the field structure will be necessary. Since the dynamo i has two field-windings and the dynamo 3 has three such windings, it will be sufficient to describe the manner of applying the three field-windings M N O to the stator structure of the dynamo 3,- when the method of applying the two field-windings K K to the stator structure of the dynamo 4: will have become plain without further description.

Let us suppose, to fix ideas, that the machine 3 is bipolar and that the magnetic frame of its stator is built up of sheets. such as shown in Fig. 2, with twelve interior longitudinal grooves parallel to the axis of the machine. If it were a question of applying a single-turn winding to such a stator to produce a magnetic axis along the lines a; m, we should manifestly lodge a single wire in each longitudinal groove, and we'should so interconnect them that the current would flow in one direction in all the wires marked plus on the left in Fig. 2 and would flow in the opposite direction in all the wires marked minus on the right of Fig. 2; but we must wind in each groove three sets of wires M N 0, any or all of which may consist of a multiplicity of turns. To this end we may proceed as follows: We may take a mandrel of proper shape and wind upon it a conductor in the shape of the conductor N of Fig. 5, and we may give to this conductor N one turn or a number of superposed turns. Similarly we wind upon the same mandrel the conductors O and M, each of as many turns as may be necessary. These three sets of conductors N M O we may secure together mechanically by a wrapping of tape. Having built one set of conductors, such as is indicated in Fig. 5, we remove it from the mandrel and build five other similar sets of conductors. We thereupon place one of the sets of conductors of Fig. 5 inside the stator structure of Fig. 2 with one straight portion in one groove and the other parallel straight portion in the diametrically opposite groove. We similarly insert the five other conducting sets of Fig.

5 into the five other pairs of diametrically opposite grooves of Fig. 2 Each conducting set has one wire or entry and one wire of exit for each circuit M N O. These wires of entry and wires of exit of the six conducting sets of the circuit M are thereupon interconnected, so that current will traverse each of the branches M in one direction to the left of w w in Fig. i and in the opposite direction to the right of w w in Fig. 4. A similar remark applies to the circuit 0; but the wires of entry and exit of the circuits N are so interconnected that those portions of these circuits which lie above the line y 1 of Fig. 4 will be traversed by currents in one direction and the portions of those circuits which lie below the line 3/ y will be traversed by currents in the opposite direction. It is thus seen that the windings O and M each tend to produce a magnetic axis along the line 50 m, which is taken at right angles to the brushes. lt is further evident that the windingN tends to produce a magnetic axis along the line gz y in the direction of the brushes that is to say, a magnetization of a kind proper to annul the effect of the armature magnetization.

in the case of the dynamo 4: we should only have two circuits K K, as has previously IIO been remarked, instead of the three circuits M N 0. To properly represent this in the drawings would mean that but two circuits should be shown in Fig. 5 and but two sections of circuits in Fig. 3. Furthermore, the outercircle of Fig. 4: would now represent but a single circuit K instead of two circuits M 0, each tending to produce a magnetic axis along :1) .1

1 may say that I have shown but a single exciter 3, since the circuit connections would be precisely the same fora number of exciters coupled in parallel. I may. furthermore, say that the total power consumed by the machines 1, 2, and a, which comprise my regulating system when used in its most perfected form, is quite small with reference to the maximum powerof the exciter. In fact, it is safe to say that if the exciter is of one-hundred-kilowatt capacity the machines 1 and 2 need only be of live-kilowatt capacity each, whereas the machine 4: need only beot' onekilowatt capacity. The proof of this it is unnecessary to give.

In what I have said above the regulating devices have been assumed as operating at a normal speed. A few words will be necessary to show how these regulating devices may be started to bring them up to speed. At the moment of starting the regulating system the switches U1 U2 U3 and the switch X are put on open circuit. The continuous current machines 2, 3, and 4c are then brought up to their normal speed by power applied to their pulleys. The exciter 3 behaves like a compound machine, building up automatically and exciting the field-circuits of the alternator. These alternator-fields are brought up to the desired voltage by manipulating a rheostat Y in the shunt field-circuits O of the exciter 3. The switch X being closed, the commutatingmachine 1 is driven as a motor by current furnished by the continuous-current machine 2, and the commutating-machine is brought up to synchronism by manipulating the fieldrheostat Z. The switches U1 U2 U3 being now closed and the field-rheostats Y and Z being cutout, the regulating system is in operation.

\Vhen 1 use the word alternator without additional modification, 1 use it in a sense broad enough to cover synchronous or asynchronous machines, and this whether the alternator is used as a generator or a motor.

I may say that my voltage regulator is particularly applicable to the alternators shown and described in my application Serial No. 140,933, filed January 28, 1902.

l elaim 1. A curren t-generator, an exciter therefor, a source of voltage having a predetermined value, a source of an opposing voltage varying with that supplied by the generator, a circuit containing a field-winding of the exciter and developing current in accordance with the resultant of the opposing voltages, whereby the generator voltage is maintained at a predetermined value, substantially as described.

2. A current-generator, an eXciter therefor, a source of voltage having a predetermined value, a source of an opposing voltage varying with the generator voltage, and a relay-dynamo having a field-winding upon which the opposed voltages are impressed and an armature-winding supplying the eXciter-field with current to maintain the generator voltage of predetermined value, substantially as described.

3. A current-generator, a shunt-wound exciter therefor, a source of voltage of predetermined value, and a source of an opposing voltage proportional to the generator voltage, the opposing voltages determining the character of a current supplied to a lield-winding of the exciter to modify the action of its shuntwinding so as to maintain the generator voltage of predetermined value, substantially as described.

4t. An alternator, an electric. l device in circuit therewith developing a voltage proportional to the line voltage, and a source of voltage of predetermined value opposed thereto, the opposing voltages determining the character of a regulating-current to keep the alternator voltage of predetermined value, substantially as described.

5. An alternator, a commutating-machine in circuit therewith developing between its brushes a continuous voltage proportional to the line voltage, and a source of continuous voltage of predetermined value opposed thereto, the opposed voltages determining the character of a regulating-current to keep the alternator voltage of in'edetermined value, substantially as described.

6. An alternator, an exciter therefor, a commutating-machine in circuit with the alternator developing between its brushes a continuous voltage proportional to the line voltage and a source of continuous voltage of predetermined value opposed thereto, the opposing voltages determining the character of current supplying the cxciter-lield to maintain the alternator voltage constant, substantially as described.

7. An alternator, an exciter therefor, a commutating-machine in circuit with the alternator developing between its brushes a continuous voltage proportional to the line voltage,

= a source of continuous voltage of predetermined value opposed thereto, and a relay-dynamo having a field-winding upon which the opposed voltages are impressed and an armature-winding supplying the eXciter-licld in a manner to maintain the alternator voltage of predetermined value, substantially as described.

8. An alternator, a shunt-wound excitcr therefor having a series field-Winding to neutralize armature reaction, a commutating-machine in circuit With the alternator developing between its brushes a continuous voltage proportional to the line voltage, and a source of continuous voltage of predetermined value opposed thereto, the opposing voltage determining the character of current supplying the exciter-field to modify the action of its shunt-Winding so as to maintain the alternator voltage constant, substantially as described.

9. An alternator, an eXciter therefor having a stator of the type of induction-machines and a series field-Windingto overcome armature reaction, a comniutating-niachine in circuit With the alternator developing between its brushes a continuous voltage proportional to the line voltage, and a source ofcontinuous voltage of predetermined value opposed thereto, the opposing voltages determining the character of current supplying the exciterfield to maintain the alternator voltage constant, substantially as described.

10. An alternator, an eXciter therefor having a series field-Winding to overcome armature reaction, a relay-dynamo energizing the eXci-ter-field, and in turn energized by a source of constant voltage and an opposed source of voltage varying with that of the line, substantially as described.

11. An alternator, an exciter therefor having a series field-Winding to overcome armature reaction, and a source of voltage of predetermined value and an opposed source of voltage varying with that of the line for supplying the eXciter-field With current to keep the alternator voltage of predetermined value, substantially as described.

12. An alternator, an exciter therefor, a commutating-machine in circuit Withthe alternator having a series field-Winding to overcome armature reaction and developing between its brushes a continuous voltage proportional to the line voltage, and a source of continuous voltage of predetermined Value opposed thereto, the opposing voltages determining the character of current supplying the eXciter-field to maintain the alternator Voltage of predetermined value, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

MAURICE LEBLANC.

Witnesses:

ALBERT DELAS, EDWARD P. MACLEAN. 

